Personally I find OsmAnd to be truly awful. The interface is stuck in the Android 1.6 era and I can't even get the online maps to show anything. Offline maps are nice but not that useful unless I am travelling overseas and don't buy a data enabled SIM card.
Yes, but OsmAnd lets me download a map for my entire country. This is important to me because I don't have a large data plan or access to Wi-Fi when I'm on the road. I also might not necessarily know exactly where I'm going to be going when I'm away.